The present invention relates to a picture scanning and recording method for maintaining a scanning head or a recording head at a focus matching position relative to the film surface applied onto an original picture drum or relative to the surface of a photoelectrical material applied to a recording drum by controlling the position of the scanning head or the recording head in a picture scanning and recording apparatus such as a color scanner etc.
In the present method there are two cases and they are identical with each other, essentially. One of the cases is to apply the present method of the scanning side of the picture scanning and recording apparatus and the other is to apply it to the recording side. However, the former case is more complicate than the latter case, so that hereinafter we will explain the former case, i.e., the more complicate case.
For example, in a color scanner of rotary drum type, positional relation between the original picture applied onto the scanning drum and a pick-up lens of the scanning head must be focus-matched relation.
However, practically, quality of material of the original picture film and thickness thereof are somewhat different from each other by those different makers thereof, accordingly, prior to carrying out scanning, manually controlling an adjusting screw by an operator is required so that the pick-up lens may be moved a minute distance in the front or rear direction relative to the original picture drum to scan the original picture so that it is in focus.
However, such adjustment is time-consuming work for the persons not proficient in the art and even for the operator it is hard to precisely adjust it, and quality of final printings is liable to be deteriorated.
In addition, the shape of the drum on which the original picture is applied, particularly, because of manufacturing precision of the size of the outside diameter of the drum, the drum size is not strictly constant with respect to its axial direction, so that, even if the operator focuses the lens, when the original picture is photoelectrically scanned, slipping off focusing point is liable to occur.